1. Field of the Invention
The present invention relates to a silica nanowire comprising silicon nanodots and a method of preparing the same, and more particularly, to a silica nanowire comprising silicon nanodots that has excellent capacitance characteristics and improved light absorbing ability.
2. Description of the Related Art
In general, nanowires are linear wires having a diameter on the order of a nanometers (1 nanometer (“nm”=10−9 meters (“m”)) and a length that is much larger than the diameter, for example, of the order of hundreds of nanometers, micrometers (1 micrometer (“μm”)=10−6 m), or millimeters (1 millimeter (mm)=10−3 m) scale. The physical properties of such nanowires depend on the diameter and length thereof.
Presently, research into methods of preparing nanoparticles and studying the physical properties of nanoparticles is being actively pursued. However, general methods of manufacturing nanowires that can produce nanowires on commercial scales are not well developed yet.
Such methods generally comprise a method that employs a template and uses techniques such as chemical vapor deposition (“CVD”), laser ablation, and the like.
The methods that use a template generally use pores having a size from several nanometers to hundreds of nanometers. These pores generally serve as nucleation sites for growing the nanowire.
For example, metal nanowires can be produced by this method by oxidizing an aluminum electrode to form aluminum oxide on its surface. The surface is electrochemically etched to form nanopores following which the electrode is dipped into a solution containing metal ions and a current is applied to stack the metal ions on the aluminum electrode through the pores so that the pores are filled with metal ions. The oxide is then removed using an appropriate process, to obtain metal nanowires.
However, such a conventional method of manufacturing nanowires is disadvantageous because it is considerably complicated and requires a long period of time, and is thus unsuitable for mass production. The diameter and length of the nanowires depend on the diameter and depth of the pores. The state of current technologies is that it is nearly impossible to form pores having a size of several nanometers and having a depth from hundreds of micrometers to several millimeters. Therefore, it is very difficult to prepare nanowires having a diameter of several nanometers and a relatively long length.
CVD is a method in which a raw material gas comprising a desired material is injected into a reactor. The raw material gas is excited by heat or by a plasma so that it is decomposed, and the desired material reaches the surface of a substrate through which it diffuses. It then emanates from another surface of the substrate in the form of nanotubes or nanowires. Examples of CVD include low pressure CVD (“LPCVD”), atmospheric pressure CVD (“APCVD”), and high pressure CVD (“HPCVD”), characterized according to the pressure of the reactor; plasma enhanced CVD (“PECVD”), which can form nanotubes or the like, at a low temperature by using a plasma.
Laser ablation is a method used to synthesize single-layered carbon nanotubes and semiconductor nanowires. Compared to other methods, nano materials with considerably high purity can be obtained via this method, and it is easy to purify the nano materials obtained using laser ablation.
Nanowires prepared using such conventional methods can be used in electronic devices such as field effect transistors (FETs), sensors, photodetectors, and the like.
As an example of such nanowires, Korean Patent Publication No. 2007-0049035 discloses a method of preparing nanowires comprising metal nanodots. However, the nanodots are formed of metal and the size and density of the metal nanodots are limited.
Therefore, there is still a need to develop new nanowires having improved electrical properties and optical properties.